The work presented in this dissertation discusses large scale flow and transport in river networks and investigates advantages and disadvantages of grid-based and vector-based river networks. This research uses the Mississippi River basin as a continental-case study and the Guadalupe and San Antonio rivers and Seine basin in France as regional-case studies. The first component of this research presents an extension of regional river flow modeling to the continental scale by using high resolution river data from NHDPlus dataset. This research discovers obstacles of flow computations for river a network with hundreds of thousands river segments in continental scales. An upscaling process is developed based on the vector-based river network to decrease the computational effort, and to reduce input file size. This research identifies drainage area as a key factor in the flow simulation, especially in a wet climate. The second component of this research presents an enhanced GIS framework for a steady-state riverine nitrogen transport modeling in the San Antonio and Guadalupe river network. Results show that the GIS framework can be applied to represent a spatial distribution of flow and total nitrogen in a large river network with thousands of connected river segment. However, time features of the GIS environment limit its applicability to large scale time-varied modeling. The third component shows a modeling regional flow and transport with consideration of stream-aquifer interactions at a regional scale at high resolution. The STICS- Eau-Dyssée combined system is implemented for entire seine basin to compute daily nitrate flux in the Seine grid river network. Results show that river-aquifer exchange has a significant impact on river flow and transport modeling in larger river networks. / text

This Master thesis focuses on a river network characteristics in the Jizerské hory Mts., northern Bohemia. This part of the Czech Republic represents an area, which was during Tertiary and Pleistocene affected by neotectonic movements. Therefore, 30 longitudinal profiles of selected rivers were constructed to determine areas influenced by tectonics most intensively. These profiles were classified into four categories according to shape of profile curve. Also valley cross sections were made on five selected rivers. Additionally, the Jizera and Jizerka rivers were studied to assess changes of their streams in the period of 19382012. On the north-western (the Jeřice river catchment) and northern (the Smědá river catchment) slopes of the Jizerské hory Mts., areas most affected by neotectonic movements were detected. Tectonically controlled valley cross sections are distinctive on the Smědá, Jizera and Kwisa rivers. On the Jizerka and Jizera rivers, lateral erosion rate ranges up to 0,5 m/year.

Water has always had a controlling influence on the earth’s evolution. Understanding and modelling the large-scale hydrological cycle is important for climate prediction and water-resources studies. In recent years large-scale hydrological models, including the WASMOD-­M evaluated in the thesis, have increasingly become a main assessment tool for global water resources. The monthly version of WASMOD-M, the starting point of the thesis, revealed restraints imposed by limited hydrological and climate data quality and the need to reduce model-structure uncertainties. The model simulated the global water balance with a small volume error but was less successful in capturing the dynamics. In the last years, global high-quality, high-resolution topographies and hydro­graphies have become available. The main thrust of the thesis was the development of a daily WASMOD-M making use of these data to better capture the global water dynamics and to parameter­ise local non-linear processes into the large-scale model. Scale independency, parsimonious model structure, and computational efficiency were main concerns throughout the model development. A new scale-independent routing algorithm, named NRF for network-response function, using two aggregated high-resolution hydrographies, HYDRO1k and HydroSHEDS, was developed and tested in three river basins with different climates in China and North America. The algorithm preserves the spatially distributed time-delay information in the form of simple network-response functions for any low-resolution grid cell in a large-scale hydrological model. A distributed runoff-generation algorithm, named TRG for topography-derived runoff generation, was developed to represent the highly non-linear process at large scales. The algorithm, when inserted into the daily WASMOD-M and tested in same three basins, led to the same or a slightly improved performance compared to a one-layer VIC model, with one parameter less to be calibrated. The TRG algorithm also offered a more realistic spatial pattern for runoff generation. The thesis identified significant improvements in model performance when 1) local instead of global climate data were used, and 2) when the scale-independent NRF routing algorithm was used instead of a traditional storage-based routing algorithm. In the same time, spatial resolution of climate input and choice of high-resolution hydrography have secondary effects on model performance. Two high-resolution topographies and hydrographies were used and compared, and new tech­niques were developed to aggregate their information for use at large scales. The advantages and numerical efficiency of feeding high-resolution information into low-resolution global models were highlighted. / Vatten har alltid varit en nyckelfaktor för jordens utveckling. Att förstå och kunna modellera det storska­liga vattenkretsloppet är betydelsefullt såväl för klimatförutsägelser som för studier av vattenresur­ser. På senare år har storskaliga hydrologiska modeller, däribland WASMOD-M som utvärderas i denna avhand­ling, i ökande utsträckning kommit att användas som huvudverktyg för utvärdering av globala vattenresurser. Den månatliga versionen av WASMOD-M, avhandlingens startpunkt, användes för att påvisa inskränk­ningar som låg i begränsande hydrologi- och klimatdata liksom behovet av att minska model­lens strukturella osäkerheter. Modellen simulerade den globala vattenbalansen med ett mycket litet volymfel (avrinningens långtidsmedelvärde) men var mindre lyckosam att efterlikna dynamiken. Under se­nare tid har globala topografiska och hydrografiska data med hög rumslig upplösning och kvalitet blivit tillgängliga. Avhandlingens huvudsakliga drivkraft var att utveckla WASMOD-M med hjälp av dessa data i syfte att bättre fånga den globala vattendynamiken och för att parametrisera lokala ickelin­jära processer i den storskaliga modellen. Under hela modellutvecklingen har skaloberoende, lågparametrise­rad modellstruktur och numerisk beräkningseffektivitet varit viktiga bivillkor. En ny skaloberoende svarstidsalgoritm, benämnd NRF (network-response function), som utnyttjar två aggregerade högupplösta hydrografier, HYDRO1k och HydroSHEDS, utvecklades och provades i tre avrinningsområden med olika klimat i Kina och Nordamerika. Algoritmen bevarar den rumsligt fördelade informationen om koncentrationstider i form av enkla responsfunktioner för vattendragsnä­tet för godtyckliga lågupplösta beräkningsrutor in en storskalig hydrologisk modell. En distribuerad algoritm för avrinningsbildning, benämnd TRG (topography-derived runoff genera­tion), utvecklades för att representera den höggradigt ickelinjära processen i större skalor. Algoritmen användes i den dagliga WASMOD-M och provades i samma tre avrinningsområden som ovan. Modellprestanda blev lika bra eller bättre än en enlagers VIC-modell fast med en parameter mindre att kalibrera. TRG-algoritmen gav ett rimligare rumsligt mönster för avrinningsbildningen. Avhandlingen har identifierat påtagliga förbättringar i modellprestanda när 1) lokala i stället för globala klimatdata användes och 2) när NRF, den skaloberoende svarstidsalgoritmen användes i stället för en traditionell magasinsbaserad svarstidsalgoritm. Samtidigt har klimatdatas rumsliga upplösning och val av högupplöst hydrografi en andra ordningens inverkan på modellprestanda. Två högupplösta topografier och hydrografier användes och jämfördes, och nya tekniker utveckla­des för att aggregera deras informationsinnehåll i stora skalor. Fördelarna och den numeriska beräkningsef­fektiviteten av högupplöst information i lågupplösta globala modeller har belysts.

Le Tibet est le plateau le plus élevé et le plus étendu au monde. La formation de ce plateau, en arrière de l’Himalaya, résulte d’interactions complexes entre facteurs tectoniques et climatiques, ainsi que de la morphologie antérieure au soulèvement. Afin d’évaluer l’influence relative de ces différents facteurs, cette thèse s’appuie sur l’étude de l’évolution du relief des bordures du plateau en couplant analyse géomorphologique, étude de la sédimentation syn-formation du plateau et reconstitution de l’exhumation à partir de la thermochronologie de basse température.Cette approche a permis de mettre en évidence que le plateau du Tibet était déjà haut, aussi bien sur ses bordures est que ouest dès 35 Ma, soit seulement 20 Ma après la collision Inde-Asie. Il apparait donc que le plateau se serait soulevé soit en un bloc, soit de façon précoce par ses marges Ouest et Est, plutôt qu’en se propageant du sud vers le nord et vers l’est comme proposé par de nombreux modèles.Dans l’Ouest Tibet, l’existence d’un réseau de drainage anciennement connecté avec celui de l’Indus, a permis le développement précoce d’un relief significatif (supérieur à 1000 m) avant 35 Ma lors de la surrection du plateau. Ce relief est ensuite préservé dans un contexte d’érosion très faible (quelques dizaine de mètres par million d’années) associé à une évacuation des produits d’érosion vers le bassin de l’Indus. Cette connexion avec l’Indus est ensuite coupée probablement suite aux mouvements de la faille du Karakorum.A l’Est, la formation du relief est probablement plus ancienne que dans l’Ouest Tibet, car vers 35 Ma cette région, bien que déjà surélevée, est caractérisée par l’existence d’un vaste réseau fluviatile en tresse, impliquant une faible pente, ainsi qu’un relief local soumis à des précipitations plus au nord. La création du relief actuel, marqué par des rivières fortement encaissées, est probablement liée à l’évolution de la mousson sud-est asiatique ainsi qu’au fonctionnement de la faille du Fleuve rouge. / Tibet is the widest and highest plateau on Earth. Tectonics, climate evolution and ante-surrection geomorphology are the main factors controlling the plateau formation. In order to assess the relative influence of these factors, we study the relief evolution on the plateau edges using geomorphic analysis, sedimentology and exhumation rates based on low-temperature thermochronometry.The results show that the western and eastern plateau edges were already at high elevation at ca 35 Ma, only 20 Ma after the India-Asia collision. This favors an “en bloc” uplift model for the plateau.In western Tibet, the hydrographic network was connected to the Indus river, allowing the early development of a >1000 m amplitude relief, probably before 35 Ma. The relief was preserved due to low erosion conditions. Western Tibet was then isolated from the Indus drainage network due to the Karakorum fault slip.The relief formation in Eastern Tibet is older than in western Tibet: at ca 35 Ma, in the Jianchuan area (northern Yunnan), which was already at high elevation, was a large braided river system. This implies a moderate regional slope. It also implies a local relief further north and significant precipitations.

Die Besiedlung von Gewässern durch Fische, ist neben abiotischen Lebensraumbedingungen auch von der Erreichbarkeit d.h. von der art-spezifischen Ausbreitungsfähigkeit sowie von Wanderhindernissen abhängig. Der erste Teil dieser Arbeit bietet die erste umfangreiche quantitative Analyse von Ausbreitungsmustern und -distanzen von Flussfischen. Aus der Fachliteratur wurden 160 empirische Datensätze aus 71 wissenschaftlichen Studien zur Ausbreitung von 62 Fischarten in Flüssen extrahiert und an leptokurse Wahrscheinlichkeits-Dichte-Funktionen (Dispersal kernel) angepasst. Es konnte bei Fischpopulationen zwischen einer stationären (ca. 2/3) und einer mobilen Komponente (ca. 1/3) unterschieden werden deren Ausbreitungsdistanzen von vier Faktoren abhängig sind: Fischlänge, Form der Schwanzflosse, Fließgewässergröße, betrachtete Zeitspanne. Der zweite Teil dieser Arbeit widmet sich dem neu entwickelten Fischausbreitungsmodell FIDIMO einem GIS-Softwareprogramm zur Modellierung und Simulation der räumlichen und zeitlichen Ausbreitungsmuster von Fischen in Flüssen unter Berücksichtigung von Wanderhindernissen. FIDIMO verknüpft konzeptionelle Überlegungen zu Ausbreitungsmodellen in verzweigten Fließgewässernetzwerken mit empirisch bestimmten leptokursen Fischausbreitungskurven unter ausschließlicher Verwendung von Free and Open Source Software. Im dritten Teil der Arbeit wurde FIDIMO zur Modellierung der Ausbreitung von 17 Fischarten angewendet um die Einflüsse von (i) Habitatqualität, (ii) Ausbreitungsfähigkeit und (iii) Fließgewässer-Fragmentierung auf die Besiedlungsmuster durch Fische zu bestimmen. Die Ergebnisse zeigen, dass die artspezifische Habitatqualität und Ausbreitungsfähigkeit die Besiedlung maßgeblich bestimmen. Dagegen wurde kein signifikanter Einfluss von Barrieren auf das Vorkommen einer Art gefunden. Über längere Zeiträume sinkt der Einfluss von Fischausbreitung auf das lokale Vorkommen einer Fischart während die Habitatqualität relativ wichtiger wird. / The colonisation of rivers by fishes is directly linked to abiotic habitat conditions but often impaired by dispersal abilities of fishes and movement constraints such as barriers. The first part of this thesis provides the first comprehensive quantitative analysis of freshwater fish movement while considering fish populations consisting of differently mobile specimens. 160 empirical datasets from 71 studies on the movement of 62 riverine fish species were analysed based on refitted leptokurtic probability-density functions (dispersal kernels). A share of one third and two thirds emerged as a general pattern of the mobile and stationary component of a fish population, respectively. Moreover, four variables were identified primarily determining dispersal distances: fish length, aspect ratio of the caudal fin, river size and time. In the second part of the thesis, the novel fish dispersal model FIDIMO is introduced. FIDIMO provides a GIS-tool for predicting and simulating spatio-temporal patterns of fish dispersal in dendritic river networks considering movement barriers. The fish dispersal model FIDIMO links conceptual considerations on dispersal modelling with empirically observed leptokurtic fish movement patterns and the strengths of geographically explicit modelling in Free and Open Source GIS. In the third part of the thesis, FIDIMO was applied for modelling dispersal of 17 fish species to disentangle the effects of (i) habitat suitability, (ii) dispersal constraints and (iii) network fragmentation on the distribution of river fishes. The results show significant positive effects of both, local-scale habitat quality and species-specific dispersal ability on the distribution of river fishes, whereas no significant effect of barriers influencing the presence of a species could be found. Over longer time periods the importance of dispersal decreased in favour of habitat suitability becoming relatively more relevant in determining species'' presence.

The PhD. thesis deals with the morphostructural evolution of the valley network of the Biala Lądecka river, (further refer as BL) during the Late Cenozoic. In this work, the selected methods as geomorphological research (morphostructural analysis, geomorphological mapping), structural-geological research (paleostres analysis) and geophysical survey on selected sites were used, to answer the questions of river basin development and its relationship with predicted tectonic activity within the area, as well as with anticipated or already known paleohydrographic changes. The BL basin is situated within the Rychlebské hory Mts. / Góry Złote (northern and eastern parts of the basin), Králický Sněžník (southern part) and the Krowiarki Mts. (western part) in Poland. The Marginal Sudetic fault zone, which represents one of the most important tectonic zones in the Central Europe, passes in vicinity of the study area as well as the regionally important Bělský fault, which passes directly through the BL basin. The results of the analysis indicate that the BL basin has undergone very complex development due to tectonic movements since Miocene up-to-day. Based on the results of the paleostress analysis, which was performed on the dated volcanites in Lutynia - Lądek Zdrój area, the parameters of the palaostress...